Again, this is lifted from my thesis which looks unlikely to ever see the light of day unless I take it off the shelves in BEL library at UQ.
Potential ambiguity arises when a term or a sentence is ambiguous in and of itself, for example, before its use in the context of a sentence or paragraph. Three types of ambiguity are categorised as potential ambiguity: lexical, syntactical, and inflective.
Lexical ambiguity is the most commonly known form of ambiguity (Reilly 1991; Walton 1996). It occurs when words have more than one meaning as commonly defined and understood. Considerable potential ambiguity arises when a word with various meanings is used in a statement of information request. For example, "bank" may variously mean the "bank" of a river (noun), to "bank" as related to aeroplane or a roller-coaster (verb), a savings "bank" (noun), to "bank" money (verb), or a "bank" of computer terminals (noun) (Turner 1987). Lexical ambiguity is often reduced or mitigated by the context of the sentence.
In the case of an information request, lexical ambiguity exists in the statement "A report of our clients for our marketing brochure mail-out". The word "report" may have several meanings, independent of its context. A gunshot report may echo across the hillside. A student can report to the lecturer. A heavy report can be dropped on the foot. Although the context may make the meaning clear, the lexical ambiguity contributes to the overall ambiguity of the statement and increases cognitive effort.
Syntactical ambiguity is a structural or grammatical ambiguity of a whole sentence that occurs in a sub-part of a sentence (Reilly 1991; Walton 1996). Syntactical ambiguity is a grammatical construct, and results from the difficulty of applying universal grammatical laws to sentence structure. An example of syntactical ambiguity is "Bob hit the man with the stick". This phrasing is unclear as to whether a man was hit with a stick, or whether a man with a stick was struck by Bob. The context can substantially reduce syntactical ambiguity. For example, knowing that either Bob, or the man, but not both, had a stick resolves the syntactical ambiguity.
Comparing the phrase "Bob hit the man with the stick" to the analogous "Bob hit the man with the scar" provides some insights. As a scar is little suited to physical, violent use, the latter formulation clearly conveys that the man with the scar was struck by Bob (Kooij 1971).
In the case of an information request, syntactical ambiguity exists in the request "A report of poor-paying clients and client managers. Determine their effect on our profitability for the last twelve months." The request is syntactically ambiguous because the end user can interpret "their" to mean the poor paying clients, the client managers, or both. Although the context may reduce or negate the ambiguity, syntactically the request is ambiguous.
As Walton (1996) notes, inflective ambiguity is a composite ambiguity, containing elements of both lexical and syntactical ambiguity. Like syntactical ambiguity, inflective ambiguity is grammatical in nature. Inflection arises where a word is used more than once in a sentence or paragraph, but with different meanings each time (Walton 1996). An example of inflective ambiguity is to use the word "scheme" with two different meanings in the fallacious argument, "Bob has devised a scheme to save costs by recycling paper. Therefore, Bob is a schemer, and should not be trusted" (Ryle 1971; Walton 1996).
In the case of an information request, inflective ambiguity exists in the example, "A report showing the product of our marketing campaign for our accounting software product". Ambiguity derives from using the word "product" in two different senses in the one statement (Walton 1996; Fowler and Aaron 1998).